Engine synchronizing mechanism



March 21, 1967 w. J. KELLY 3,309,871

ENGINE SYNCHRONI Z ING MECHANI SM Filed Jan. '7. 1964 3 Sheets-Sheet l vINVENTOR. -nu 144772 477 71/9621 March 1957 w. J. KELLY 3,3,87E

ENGINE SYNCHRONIZING MECHANISM Filed Jan. '7, 1964 3 Sheets-Sheet Q MiMi m mzw United States Patent ()fiice 3,309,871 Patented Mar. 21, 19673,369,871 ENGINE SYNCHRGNIZING MECHANISM Winton J. Kelly, 485 Westwood,Birmingham, Mich. 48009 Filed Jan. 7, 1964, Ser. No. 336,310 11 Claims.(Cl. 6097) This invention relates to control systems and apparatus forcontrolling the relative speeds of a pair of prime movers deliveringrotative energy.

More specifically the present invention is shown and described as acontrol system for controlling the relative speeds of a pair of internalcombustion engines for marine use or the like. When a pair of enginesare utilized together to propel a boat it is important that both enginesbe operated in synchronism or at the same speed. Where separate throttlecontrols for each engine are provided it is common to determine enginesynchronization by the use of tachometer readings. These, however, areinaccurate and make engine synchronism difficult; the use of tachometersis also awkward when synchronism is desired over a wide range of enginespeeds since separate throttle adjustments must be made at each speed.With the present invention synchronism can be attained automatically andsubstantially simultaneously at any desired speed over the operatingspeed range of the engines. It is a general object of the presentinvention to provide apparatus for controlling the relative speeds of apair of prime movers delivering rotative energy. It is another object ofthe present invention to provide apparatus for automatically andsubstantially simultaneously synchronizing a pair of engines at anyspeed within the operating speed range of the engines.

In the present invention, the engines can be either operated insynchronism from a single throttle control or each can be operatedindividually through separate throttle controls. Thus it is anotherobject of this invention to provide apparatus for controlling the speedof a pair of engines which has one mode of operation in which theengines are operated in synchronism through a single throttle controland a second mode in which each engine can be operated through its ownthrottle control.

In the control system of the present invention a novel differential gearassembly is used in a novel combination which provides the meritoriousresults briefly noted above. Therefore it is another general object ofthis invention to provide a differential gear assembly of a novelconstruction. It is a further object of this invention to provide anovel combination for controlling the speed of a pair of engines whichcombination includes a differential gear assembly.

Other objects, features, and advantages of the present invention willbecome apparent from the subsequent de scription and the appendedclaims, taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a combined electrical and mechanical schematic diagram withthe control assemly of the present invention shown in elevation andshown in operative relationship with other members of a working systemshown pictorially and in block form;

FIGURE 2 is an end view of the control assembly of FIGURE 1;

FIGURE 3 is a sectional view with some parts shown broken away of thecontrol assembly of FIGURE 2 taken substantially along the line 3-3;

FIGURE 4 is a sectional view of the control assembly of FIGURE 3 takensubstantially along the line 44;

FIGURE 5 is a sectional view of the control assembly of FIGURE 3 takensubstantially along the line 55; and

FIGURE 6 is a sectional view of the control assembly of FIGURE 3 takensubstantially along the line 66 in FIGURE 4.

In general and looking now to FIGURE 1, a pair of internal combustionengines 10 and 12, whose speeds or rotational velocities are to besynchronized, are shown connected to a control assembly 14 whichcomprises a differential gear assembly 16 and a clutch and leverassembly 18. The engine 10 is the master engine and has a throttle lever20 which is representatively shown to be connected to its throttle via alinkage 22 whereby the speed of the engine 10 can be varied bymanipulation of the lever 20. The engine 12 is the follower or slaveengine and has a throttle lever 24 which is representatively shown to beconnected to the clutch and lever assembly 18 via linkage 26 and thenceto the throttle of slave engine 12 via linkage 28. As will be seen thecontrol assembly 14 has one mode of operation in which the throttle ofthe slave engine 12 is actuated only by manipulation of the throttlelever 24 and a second mode of operation in which the throttle of theslave engine 12 is disconnected from the lever 24 and is actuated tomaintain the speed of the slave engine 12 in synchronism with the speedof the master engine 10. The rotational outputs of the engines 10 and 12are connected to one end of flexible cable assemblies representativelyshown by the dotted lines 39 and 32, respectively, which have theiropposite ends connected to the differential gear assembly 16 of thecontrol assembly 14, whereby indications of the rotational speeds of thetwo engines are provided to the control assembly 14. In the second modeof operation the difference in speed between engines 10 and 12 is sensedand the throttle of the slave engine 12 is automatically actuated by thecontrol assembly 14 to bring the speed of the slave engine 12 intosynchronism with the speed of the master engine 10. Thus as the speed ofthe master engine 10 is varied by manipulation of the throttle lever 20,the speed of the slave engine 12 is automatically similarly varied andbrought into synchronism.

Looking now to FIGURES l and 3, the flexible cables 30 and 32 areconnected to worm shaft assemblies 34 and 36, respectively, which form apart of the differential gear assembly 14. Since the worm shaftassemblies 34 and 36 are identical only the details of one will bedescribed. Looking now to FIGURE 5, the worm shaft assembly 34 comprisesa tubular worm member 38 which is fixed upon a shaft 40 having squaresection end portions 42 and 44 which extend axially outwardly onopposite sides of the worm member 38. A pair of brass tubular supportingsleeves 46 and 48 have square bores 59 and 52, respectively, and matablyreceive the end portions 42 and 44 respectively. Thus the sleeves 46,48, worm member 38, and shaft 40 rotate together. The worm assemblies 34and 36 are supported in an elongated body member 54 having a circularbore 56 extending longitudinally therethrough and are located intransversely extending, parallel, longitudinally spaced bores 58 and 60,respectively, which intersect and communicate with the radial extremityof the bore 56. The worm member 38 of assembly 34 and worm member 62 ofassembly 36, are located at these areas of intersection and extendpartially within the bore 56. Considering the worm assembly 34, thesleeves 46 and 48 are journaled within male connector members 64 and 66,respectively, which members are supported in opposite ends of the bore58. The male connector members 64 and 66 are of a conventionalconstruction and terminate in threaded portions which are engageablewith complementarily threaded female connectors 68 and 70, respectively.The female connector 68 is a part of the flexible cable assembly 30 andincludes a flexible cable 69 which cable terminates in a square sectionportion which fits matably within the similarly shaped bore wherebyrotation of the cable 69 rotates the worm assembly 34 via the sleeve 46.Thus the worm shaft 34 is rotated by the engine 10 either at the speedof the engine or at a speed which is in direct proportion therewithdepending on the means by which the cable assembly is connected to theengine 10. A female connector is connected to male connector member 66and is a part of a flexible cable assembly 72 which is similar inconstruction to the flexible cable assembly 30 and which is shown to beconnected to a tachometer T1 whereby the rotational speed of the wormassembly 34 and hence of the master engine 10 can be read directly.

The worm assembly 36, which is similar in construction to worm assembly34, is connected in a similar manner to slave engine 12 via the flexiblecable assembly 32. A flexible cable assembly 76 is connected from theopposite side of the worm assembly 36 to a tachometer T2 whereby thespeed of the worm assembly 36 and hence of the slave engine 12 can beread directly. The flexible cable assemblies 32 and 76 are similar inconstruction to the flexible cable assembly 30 and hence are notdescribed in detail. Note that the flexible cable assemblies 30 and 32are connected to their respective worm shaft assemblies 34 and 36 atopposite sides of the body member 54 whereby the assemblies 34 and 36are rotated in opposite directions.

A main drive shaft 78 extends coaxially of the bore 56 and has itsrearward end journaled within a bore 80 in an end plate 82 which isfixed to the rearward end of the body member 54 and is journaled withinand extends substantially longitudinally beyond a through bore 84 in anend plate 86 which is fixed to the forward end of the body member 54.End seals 89 and 91 are located between end plates 82 and 86,respectively, and the respective ends of the body member 54 with theplates 82, 86 being fixed to the body member 54 by bolts such as 87. Apair of identical worm gear assemblies 88 and are located within thebore 56 in the body member 54 and are journaled for rotation upon themain drive shaft 78 and include worm gears 92 and 94, respectively,which are engageable with the worm members 38 and 62, respectively. Theworm gear 92 is fixed to a differential side gear 96 by means of asleeve 98 which is concentrically disposed over and welded toconfronting sleeve portions 100 and 102 of the worm gear 92 and sidegear 96, respectively. In a like manner, the worm gear 94 is fixed to adifferential side gear 104, which is identical to side gear 96, via asleeve 106. The side gears 96 and 104 are located within oppositelyfacing side bores 108 and 110, respectively,

located on opposite axial sides of a generally circularly sectionedpinion carrier assembly 112 which is concentrically fixed upon the driveshaft 78 between the side gears 96 and 104.

The carrier assembly 112 is made with identical, annular housingsections 114 and 116 which are secured together by screws such as 123and with the halves assembled with their respective bores 108 and facingoppositely outwardly. Looking now to FIGURES 3, 4 and 6, the housingsections 114 and 116 have axially extending bores 118 and 120 in theirrespective confronting surfaces 122 and 124 which bores are radiallyspaced from the central axis of the assembly 112 and partially radiallyintersect and communicate with the associated one of the outwardlyfacing side bores 108 and 110. The surface 124 has a second axial bore126 (see FIGURES 4 and 6) which extends axially to a lesser extent thanand radially intersects the bore 120. An axial bore 128 in surface 122similarly radially intersects bore 118.

On assembling the identically formed sections 114 and 116 each of thebores of the pair of bores 118, 126 and of the pair of bores 120, 128 islocated coaxially oppositely from the other of that pair; the pairs ofbores 118, 126 and 120, 128 define thereby a pair of axially offset,radially communicating chambers 130 and 132, respectively, in

which differential pinions, 134 and 136, respectively, are rotatablymounted via pins 138 and 140, respectively. Since the chambers 138, 132are axially offset, the pinions 134 and 136 are axially staggeredrelative to each other and have their inner end portions in meshedengagement with each other via the opening radially communicatingchambers 130 and 132 and have their outer end portions in meshedengagement with side gears 96 and 104, respectively, via the openingsradially communicating bore 120 with side bore 110 and bore 118 withside bore 108.

A locking key or bar 142 is pinned to the main shaft 78 via pin member144 and fits matably within a pair of diametrically extending,confronting slots in faces 122 and 124 whereby rotation of the pinioncarrier assembly 112 results in rotation of the main shaft 78.

As will be seen, the main shaft 78 will rotate only when the wormassemblies 34 and 36 rotate at different speeds in opposite directions.Thus when the rotational speeds of worm assemblies 34 and 36 are equaland opposite the rotational speeds of worm gears 92, 94 and side gears96 and 104 are equal and opposite and likewise the rotational speeds ofthe differential pinions 134 and 136 are equal and opposite; in thiscondition the pinion carrier assembly 112 and hence main shaft 78 arestationary. If the rotational speed of the worm assembly 34 exceeds thatof the worm assembly 36 the pinion carrier assembly 112 will rotate inthe direction of rotation of the worm gear assembly 88 and at one-halfof the absolute difference in rotational speeds between worm gearassemblies 88 and 90. Similarly, the carrier 112 will rotate in anopposite direction if the rotational speed of the worm assembly 36exceeds that of the worm assembly 34. Thus the main shaft 78 willprovide a rotational output signal via the pinion carrier assembly 112by rotating in one direction when the speed of the master engine 10exceeds that of the slave engine 12 and by rotating in an oppositedirection when the converse is true. Because of the high speeds of theengines involved and in order to provide for a relative low speed ofrotation of the shaft 78, a substantial gear ratio is provided betweenworms 38 and 62 and their respective worm gears 92 and 94.

In conventional differential constructions it is common to use bevelgears. In the differential gear assembly 16 of the present inventionexcept for the worms 38 and 62 all of the other gears are spur gears.This latter feature permits a simpler construction since it eliminatesthe need to take up thrust loads which are present in a bevel gearconstruction. Note also that the corresponding components of the wormassemblies 34, 36, the worm gear assemblies 88, 90, the pinions 134, 136and housing sections 114, 116 are identical thus simplifyingconstruction and assembly of the differential gear assembly 16.

The forward end of the shaft 78 is connected to the clutch and leverassembly 18 which, in the second mode of operation to be described, isactuated responsively to rotation of the shaft 78 for controlling thethrottle of the slave engine 12.

Considering first the first mode of operation, a manual throttle controllever 140 is located adjacent the forward end plate 86 upon the shaft 78and can be pivoted thereon and is held axially on its rearward side bythe end plate 86 and on its forward side by a collar 142 which is pinnedto shaft 78. As shown in FIGURE 1 the manual lever 140 is connected tothe throttle lever 24 for the slave engine 12 via linkage 26 whereby themanual lever 140 can be pivoted about shaft 78 by manipulation of thelever 24. A magnetic clutch assembly 144 is located on the shaft 78adjacent the manual lever 140 and includes a magnet assembly 145supported for axial movement on shaft 78 and a flat circular clutchplate 146 which is fixed at the forward termination of the shaft 78. Theaxially movable magnet assembly 145 includes an annularly wound magneticcoil 148 located between inner and outer annular shells 150 and 152,respectively. The inner shell 150 has a radially outwardly extendingflange portion 154 at its rearward end which is radially matable againstthe inner surface of the outer shell 152 and which axially engages aradially inwardly extending lip 156 at the same end of the outer shell152. An annular washer 158 is located between the shells 150 and 152 attheir forward ends. The washer 158 is made of plastic for a purpose tobe presently seen. The outer shell 152 has it forward face 153 locatedslightly axially beyond the forward extremities of the inner shell 150and the washer 158 for a purpose to be seen.

The inner shell 150 is fixed upon a bearing sleepe 160 which isrotatably supported on the shaft 78. Thus the movable magnet assembly145 is supported on the shaft 78 for axial movement and is free to pivotabout the shaft 78. A coil spring 159 is located about the shaft 78between the clutch plate 146 and the forward end of the bearing sleeve160 and is under a compressive preload and urges the movable magnetassembly 145 towards the manual throttle control lever 14%) to aposition at which the opposite end of the bearing sleeve 16 is inengagement with the stop collar 142. A radial slot 162 is formed in thelip 156 of the outer shell 152 which with the movable magnet assembly145 in its rearward position engageably receives the manual throttlecontrol lever 149. Thus, with the magnet assembly 145 in its rearwardposition and with the manual throttle control lever 146 located withinthe slot 160, the lever 140, as it is rotated about the shaft 78,similarly rotates the magnet assembly 145.

An automatic throttle control lever 161 is fixed to the magnet assembly145 by a split ring portion 163 which is located about the outer shell152 and which is drawn together into engagement with the outer shell 152by means of a bolt 165 which engages both halves. An arm portion 167 oflever 161 is connected to the linkage 28 which is in turn connected tothe throttle of the slave engine 12. Thus with the magnet assembly 145and manual control lever 148 rotatably locked together, the throttle ofthe slave engine 12 can be manually controlled by manipulation of thethrottle lever 24. Note that at this time the magnet assembly 145 ismovable separately from the shaft 73 and hence the throttles of themaster engine and slave engine 12 can be controlled independently ofeach other. This, then, is the first mode of operation previouslydescribed. Note that in this mode of operation the rotation of the shaft78 has no effect on the throttle of either engine 10 or 12 and that inthe case of a difference in rotational speeds the shaft 78 simplyrotates freely in the appropriate direction. As will be seen, therotation of the shaft 78 is utilized in the second mode of operation.

Looking now to FIGURE 1, one side of the coil 148 is electricallyconnected to one side of a battery B via a conductor 164 and the otherside of coil 148 is connected to the opposite side of the battery B viaconductors 166 and 168 which are serially connected by a switch S. Withswitch S opened the coil 148 is not energized and the magnet assembly145 is located in its rearward position as shown in FIGURE 3. The outerand inner shelis 158, 152 and clutch plate 146 are of a material havinga relatively high permeability as compared to the material of theannular washer 158 such that when the coil 148 is energized the lines offlux created thereby fiow from one end of the coil 148 through thewasher 158 and air gap between the washer 158 and the clutch plate 146and pass through the clutch plate 146 and back to the opposite end ofthe coil 148. Thus a magnetic force is created attracting the movablemagnet assembly 145 towards the clutch plate 146. When switch S isclosed the coil 148 is energized and the magnet assembly 145 is movedaxially forwardly on the main shaft 78 until the forward surface 153 ofthe outer shell 152 engages the clutch plate 146. At the same time, withthe magnet assembly 145 in its forward position, the slot 162 is locatedaway from the manual control lever 1413 thereby disengaging the magnetassembly 145 and lever 140. Thus manipulation of control lever by lever24 will not affect the position of the automatic lever 161 and hence ofthe throttle for the slave engine 12. However, with the magnet assemblyin engagement with the clutch 146, the magnet assembly 145 and automaticlever 161 are moved in accordance with the rotation of the shaft 78. Aspreviously noted, the shaft 78 will rotate in one direction or the otherdepending upon which of the engines 10 and 12 is rotating the fastestwith the speed of rotation of the shaft 78 being a direct function ofthe magnitude of the difference in speeds. The linkage 28 is connectedto the throttle of the slave engine 12 and the automatic control lever161 such that rotation of shaft 78 and of lever 161 will always be in adirection such as to operate on the throttle of the slave engine 12 tobring the speed of the slave engine 12 into synchronism with that of themaster engine 10.

Thus in the second mode of operation, the switch S is closed energizingthe coil 148 thereby actuating the magnet assembly 145 into engagementwith the clutch 146 whereby the assembly 145 is rotated with the shaft78. Rotation of shaft 78 and hence of the automatic lever 161 is in adirection to actuate the throttle of the slave engine 12 via the linkage28 to bring the slave engine 12 to the same speed as the master engine10. Corrective rotation of the shaft 78 continues until the rotationalspeeds of both engines 10 and 12 are equal; at this time the carrier 112of the differential gear assembly 16 does not rotate and the shaft 78 isstationary. By manipulating the throttle lever 20 for the master engine10, the speed of the master engine 10 can be selectively varied. As thespeed of master engine 10 is increased the rotational speed of wormassembly 34 is increased relative to that of the worm assembly 36. Thisdifference in rotational speed results in rotation of the carrier 112,shaft 78, and lever 161 in one direction to increase the speed of theslave engine 12. In a similar manner, when the speed of master engine 10is decreased, the speed of worm assembly 34 is decreased relative tothat of the worm assembly 36 resulting in rotation of the carrier 112,shaft 78, and lever 161 in an opposite direction to decrease the speedof the slave engine 12. Thus the speed of the slave engine 12 isautomatically synchronized with that of the master engine 10 as thespeed of the latter engine is varied by manipulation of the lever 21Note that the forward surface 153 frictionally engages the clutch 146;thus in the event that either of the engines 10 or 12 loses speed due tostalling, etc., and the automatic control lever 161 is moved to itscorresponding extreme position the surface 153 and clutch 146 can slip,thereby avoiding damage to the parts. As an additional safety measure, aspring member 155 (FIGURE 1) is connected to the throttle of the slaveengine 12 and is normally under tension and acting in a direction tourge that throttle to a closed position; thus in the event that eitherof the linkages 26 or 28 break with the apparatus in the first mode ofoperation or if linkage 28 breaks with the apparatus in the second modeof operation, the slave engine will automatically be brought to a closedthrottle condition. If separate manual control of the engines 14 and 12is desired the switch S is opened deenergizing the coil 148 with thecoil spring 159 moving the magnet assembly 145 rearwardly whereby themanual control lever 140 can again engage the slot 162 and whereby thethrottle of the slave engine 12 can be controlled by manipulation of thelever 24; this again places the apparatus in the first mode of operationin which operation of the differential gear assembly 16 has no affect onthe automatic lever 161 and hence on the throttle of the slave engine12.

In the apparatus shown, the control assembly 14 has been described tohave a second mode of operation to automatically bring the speed of theslave engine 12 to the speed of the master engine 10. By providing adifference in gear ratios in the differential gear assembly 16 thecontrol assembly 14 in the second mode of operation would automaticallybring the speed of the slave engine 12 to some selected ratio of thespeed of the master engine 10.

Thus the control assembly 14 of the present invention provides two modesof operation for controlling the speeds of a pair of engines, a firstmode permitting in dividual control of the speeds of each engine and asecond mode which provides for automatic synchronization of the speed ofone engine as the speed of the other engine is varied. As has beenshown, the invention makes use of a differential gear assembly 16 whichis of a novel construction and which is economical to manufacture.

While it will be apparent that the preferred embodiment of the inventiondisclosed is well calculated to fulfill the objects above stated, itwill be appreciated that the invention is susceptible to modification,variation and change without departing from the proper scope or fairmeaning of the subjoined claims.

What is claimed is:

1. A control assembly for controlling the rotational speed of master andslave prime movers having master and slave control mechanisms,respectively, operable for determining their speeds, comprising: firstmeans connected to the master control mechanism and being selectivelyactuable for actuating the master control mechanism, second meansconnectible to the slave control mechanism of the slave prime mover andbeing selectively actuable when connected for actuating the slavecontrol mechanism, a rotatable member, differential gear means includingsaid rotatable member and connected to the master and slave prime moversfor sensing their speeds and for providing a first rotational signalvarying in magnitude in accordance with variations in the magnitude ofthe rotational speed of the master and a second rotational signalvarying in magnitude in accordance with variations in the magnitude ofthe rotational speed of the slave and for providing rotation of saidrotatable member in one direction responsively to the magnitude of saidfirst signal exceeding that of said second signal and in an oppositedirection responsively to the magnitude of said second signal exceedingthat of said first signal, connecting means actuable for connecting saidrotatable member to the slave control mechanism and for actuating theslave control mechanism for increasing and decreasing the rotationalspeed of the slave prime mover in accordance with rotation of saidrotatable member in said one and opposite directions, respectively, andactuating means selectively actuable to one condition for connectingsaid second means to the slave control mechanism and for deactuatingsaid connecting means and to a second condition for disconnecting saidsecond means from the slave control mechanism and for actuating saidconnecting means.

2. A control assembly for controlling the rotational speed of master andslave prime movers having master and slave control mechanisms,respectively, operable for determining their speeds, comprising firstmeans connected to the master control mechanism and being selectivelyactuable for actuating the master control mechanism, second meansconnectible to the slave control mechanism and being selectivelyactuable when connected for actuating the slave control mechanism, arotatable member, difierential gear means including said rotatablemember and connected to the master and slave prime movers for sensingtheir speeds and for providing a first rotational signal varying inmagnitude in accordance with variations in the magnitude of therotational speed of the master and a second rotational signal varying inmagnitude in accordance with variations in the magnitude of therotational speed of the slave and for providing rotation of saidrotatable member in one direction responsively to the magnitude of saidfirst signal exceeding that of said second signal and in an oppositedirection responsively to the magnitude of said second signal exceedingthat of said first signal, connecting means actuable for connecting saidrotatable member to the slave control mechanism and for actuating theslave control mechanism for increasing and decreasing the rotationalspeed of the slave prime mover in accordance with rotation of saidrotatable member in said one and opposite directions, respectively, andactuating means selectively actuable to one condition for connectingsaid second means to the slave control mechanism and for deactuatingsaid connecting means and to a second condition for disconnecting saidsecond means from the slave control mechanism and for actuating saidconnecting means, said actuating means comprising a clutch assemblyhaving a first member fixed to said rotatable member for rotationtherewith and a second member supported on said rotatable member forrotation relative thereto and being normally axially spaced from saidfirst member and energizing means selectively actuable for moving saidsecond member axially into frictional engagement with said first memberwhereby said first member and said second member are rotated togetherwith said rotatable member, said second means including a first levermember fixedly connected to said second member for movement therewith,first linkage means connecting said first lever member to the slavecontrol mechanism, a second lever member supported on said rotatablemember for rotation relative thereto and being engaged with said secondmember for rotation therewith when said second member is in its positionaxially spaced from said first member whereby said second lever memberand said second member rotate together and being disengaged from saidsecond member when said second member is in engagement with said firstmember, and selectively operable means connected to said second levermember for selectively rotating said second lever member about saidrotatable member.

3. A control assembly for controlling the rotational speed of master andslave prime movers having master and slave control mechanisms,respectively, operable for determining their speeds, comprising: firstmeans connected to the master control mechanism and being selectivelyactuable for actuating the master control mech anism, second meansconnectible to the slave control mechanism and being selectivelyactuable when connected for actuating the slave control mechanism, arotatable member, differential gear means including said rotatablemember and connected to the master and slave prime movers for sensingtheir speeds and for providing a first rotational signal varying inmagnitude in accordance with variations in the magnitude of therotational speed of the, master and a second rotational signal varyingin magnitude in accordance with variations in the magnitude of therotational speed of the slave and for providing rotation of saidrotatable member in one direction responsively to the magnitude of saidfirst signal exceeding that of said second signal and in an oppositedirection responsively to the magnitude of said second signal exceedingthat of said first signal, connecting means actuable for connecting saidrotatable member to the slave control mechanism and for actuating theslave control mechanism for increasing and decreasing the rotationalspeed of the slave prime mover in accordance with rotation of saidrotatable member in said one and opposite directions, respectively, andactuating means selectively actuable to one condition for connectingsaid second means to the slave control mechanism and for deactuatingsaid connecting means and to a second condition for disconnecting saidsecond means from the slave control mechanism and for actuating saidconnecting means, said actuating means comprising a clutch assemblyhaving a first member fixed to said rotatable member for rotationtherewith and a second member supported on said rotatable member forrotation relative thereto and being normally axially spaced from saidfirst member and energizing means selectively actuable for moving saidsecond member axially into frictional engagement with said first memberwhereby said first member and said second member are rotated togetherwith said rotatable member, said second means including a first levermember fixedly connected to said second member for movement therewith,first linkage means connecting said first lever member to the mechanismof the slave engine, a second lever member supported on said rotatablemember for rotation relative thereto and being engaged in said secondmember for rotation therewith when said second member is in its positionaxially spaced from said first member whereby said second lever memberand said second member rotate together and being disengaged from saidsecond member when said second member is in engagement with said firstmember, and selectively operable means connected to said second levermember for selectively rotating said second lever member about saidrotatable member, said clutch assembly being a magnetic clutch andhaving a coil fixedly located in said second member and beingenergizable for moving said second member axially into engagement withsaid first member, and said energizing means including a source ofelectrical potential and a switch connected across said coil.

4. A control assembly for controlling the rotational speed of master andslave prime movers with each prime mover having a mechanism operable forcontrolling its speed, comprising: a rotatable member, differential gearmeans including said rotatable member and connected to the master andslave prime movers for sensing their speeds and for providing a firstrotational signal substantially reduced in magnitude relative to themagnitude of the sensed speed and varying in magnitude in accordancewith variations in the magnitude of the rotational speed of the masterand a second rotational signal substantially reduced in magnituderelative to the magnitude of the sensed speed and varying in magnitudein accordance with variations in the magnitude of the rotational speedof the slave and for providing rotation of said rotatable member in onedirection responsively to the magnitude of said first signal exceedingthat of said second signal and in an opposite direction responsively tothe magnitude of said second signal exceeding that of said first signal,and means connecting said rotatable member to the mechanism forcontrolling the rotational speed of the slave prime mover and foractuating that mechanism for increasing and decreasing the rotationalspeed of the slave prime mover in accordance with rotation of saidrotatable member in said one and opposite directions, respectively, saiddifierential gear means including first and second worms connected forrotation in opposite directions by the master and slave prime movers,respectively, a pinion carrier assembly fixed to said shaft and havingfirst and second pinions in mutual engagement, first gear meansconnecting said first worm and said first pinion by geared engagement,second gearmeans connecting said second Worm and said second pinion bygeared engagement, said pinion carrier assembly including a housingfixed to said rotatable member for rotation therewith and supportingsaid first and second pinions for rotation about axes locatedeccentrically relative to the axis of said rotatable member.

5. A control assembly for controlling the rotational speed of master andslave prime movers with each prime mover having a mechanism operable forcontrolling its speed, comprising a rotatable member, difierential gearmeans including said rotatable member and connected to the master andslave prime movers for sensing their speeds and for providing a firstrotational signal substantially reduced in magnitude relative to themagnitude of the sensed speed and varying in magnitude in accordancewith variations in the magnitude of the rotational speed of the masterand a second rotational signal substantially reduced in magnituderelative to the magnitude of the sensed speed and varying in magnitudein accordance With variations in the magnitude of the rotational speedof the slave and for providing rotation of said rotatable member in onedirection responsively to the magnitude of said first 1% signalexceeding that of said second signal and in an opposite directionresponsively to the magnitude of said sec- -ond signal exceeding that ofsaid first signal, and means connecting said rotatable member to themechanism for controlling the rotational speed of the slave prime moverand for actuating that mechanism for increasing and decreasing therotational speed of the slave prime mover in accordance with rotation ofsaid rotatable member in said one and opposite directions, respectively,said differential gear means including first and second worms connectedfor rotation in opposite directions by the master and slave primemovers, respectively, a pinion carrier assembly fixed to said shaft andhaving first and second pinions in mutual engagement, first gear meansconnecting said first worm and said first pinion by geared engagement,second gear means connecting said second Worm and said second pinion bygeared engagement, said pinion carrier assembly including a housingfixed to said rotatable member for rotation therewith and supportingsaid first and second pinions for rotation about axes locatedeccentrically relative to the axis of said rotatable member, said firstgear means comprising a first Worm gear and first side gear fixedtogether and supported on said rotatable member for rotation relativethereto with said first worm gear and said first side gear being inengagement with said first worm and said first pinion, respectively,said second gear means comprising a second Worm gear and second sidegear fixed together and supported to said rotatable memher for rotationrelative thereto with said second Worm gear and said second side gearbeing in engagement with said second worm and said second pinion,respectively.

6. A control assembly for controlling the rotational speed of master andslave prime movers With each prime mover having a mechanism operable forcontrolling its speed, comprising: a rotatable member, differential gearmeans including said rotatable member and connected to the master andslave prime movers for sensing their speeds and for providing a firstrotational signal substantially reduced in magnitude relative to themagnitude of the sensed speed and varying in magnitude in accordancewith variations in the magnitude of the rotational speed of the masterand a second rotational signal substantially reduced in magnituderelative to the magnitude of the sensed speed and varying in magnitudein accordance with variations in the magnitude of the rotational speedof the slave and for providing rotation of said rotatable member in onedirection responsively to the magnitude of said first signal exceedingthat of said second signal and in an opposite direction responsive tothe magnitude of said second signal exceeding that of said first signal,and means connecting said rotatable member to the mechanism forcontrolling the rotational speed of the slave prime mover and foractuating that mechanism for increasing and decreasing the rotationalspeed of the slave prime mover in accordance with rotation of saidrotatable member in said one and opposite directions, respectively, saiddifferential gear means including first and second Worms connected forrotation in opposite directions by the master and slave prime movers,respectively, a pinion carrier assembly fixed to said shaft and havingfirst and second pinions in mutual engagement, first gear meansconnecting said first worm and said first pinion by geared engagement,second gear means connecting said second worm and said second pinion bygeared engagement, said pinion carrier assembly including a housingfixed to said rotatable member for rotation therewith and supportingsaid first and second pinions for rotation about axes of said first andsecond pinions located eccentrically relative to the axis of saidrotatable member, said first gear means comprising a first worm gear andfirst side gear fixed together and supported on said rotatable memberfor rotation relative thereto with said first worm gear and said firstside gear being in engagement with said first worm and said firstpinion, respectively, said second gear means comprising a second wormgear and second side gear fixed together and supported on said rotatablemember for rotation relative thereto with said second worm gear and saidsecond side gear being in engagement with said second worm and saidsecond pinion, respectively, said housing comprising a pair of identicalhousing sections joined together at confronting surfaces and havingopposite end surfaces, each of said opposite end surfaces having anaxially extending recess concentric with said rotatable member andreceiving one of said first and second side gears, each of saidconfronting surfaces having a pair of axially extending openings thereinwith each of said openings of one pair being located coaxially with oneof said openings of the other pair to define a pair of cavitieseccentrically located relative to said rotatable member, each of saidcavities housing one of said pinions and being in radial communicationwith each other whereby said pinion gears are mutually engaged and beingaxially olfset relative to each other with one of said cavities being inradial communication with one of said recesses and with the other ofsaid cavities being in radial communication with the other of saidrecesses whereby said first and second pinions are engaged with saidfirst and second side gears, respectively.

7. A control assembly for controlling the rotational speed of master andslave prime movers having master and slave control mechanisms,respectively, operable for determining their speeds, comprising: firstmeans connected to the master control mechanism and being selectivelyactuable for actuating the master control mechanism, second meansconnectible to the slave control mechanism and being selectivelyactuable When connected for actuating the slave control mechanism, arotatable member, differential gear means including said rotatablemember and connected to the master and slave prime movers for sensingtheir speeds and for providing a first rotational signal varying inmagnitude in accordance with variation in the magnitude of therotational speed of the master and a second rotational signal varying inmagnitude in accordance with variations in the magnitude of therotational speed of the slave and for providing rotation of saidrotatable member in one direction responsively to the magnitude of saidfirst signal exceeding that of said second signal and in an oppositedirection responsively to the magnitude of said second signal exceedingthat of said first signal, connecting means actuable for connecting saidrotatable member to the slave control mechanism and for actuating theslave control mechanism for increasing and decreasing the rotationalspeed of the slave prime mover in accordance with rotation of saidrotatable member in said one and opposite directions, respectively, saiddifferential gear means including first and second worms connected forrotation in opposite directions by the master and slave prime movers,respectively, a pinion carrier assembly fixed to said shaft and having.rst and second pinions in mutual engagement, first gear meansconnecting said first worm and said first pinion by geared engagement,second gear means connecting said second worm and said second pinion bygeared engagement, said pinion carrier assembly including a housingfixed to said rotatable member for rotation therewith and supportingsaid first and second pinions for rotation about axes locatedeccentrically relative to the axis of said rotatable member, said firstgear means comprising a first worm gear and first side gear fixedtogether and supported on said rotatable member for rotation relativethereto with said first Worm gear and said first side gear being inengagement with said first worm and said first pinion, respectively,said second gear means comprising a second worm gear and second sidegear fixed together and supported on said rotatable member for rotationrelative thereto with said second worm gear and said second side gearbeing in engagement with said second Worm and said second pinion,respectively, said housing comprising a pair of identical housingsections joined together at confronting surfaces and having opposite endsurfaces, each of said opposite end surfaces having an axially extendingrecess concentric with said rotatable member and receiving one of saidfirst and second side gears, each of said confronting surfaces having apair of axially extending openings therein with each of said openings ofone pair located coaxially with one of said openings of the other pairto define a pair of cavities eccentrically located relative to saidrotatable member, each of said cavities housing one of said pinions andbeing in radial communication with each other whereby said pinion gearsare mutually engaged and being axially offset relative to the other withone of said cavities in radial com. munication with one of said recessesand with the other of said cavities in radial communication with theother of said recesses whereby said first and second pinions are engagedwith said first and second side gears, respectively, and actuating meansselectively actuable to one condition for connecting said second meansto the slave control mechanism and for deactuating said connecting meansand to a second condition for disconnecting said second means from theslave control mechanism and for actuating said connecting means, saidactuating means comprising a clutch assembly having a first member fixedto said rotatable member for rotation therewith and a second membersupported on said rotatable member for rotation relative thereto andbeing normally axially spaced from said first member and energizingmeans selectively actuable for moving said second member axially intofrictional engagement with said first member whereby said first memberand said second member are rotated together with said rotatable member,said second means including a first lever member fixedly connected tosaid second member for movement therewith, first linkage meansconnecting said first lever member to the mechanism of the slave engine,a second lever member supported on said rotatable member for rotationrelative thereto and being engaged With said second member for rotationtherewith when said second member is in its position axially spaced fromsaid first member whereby said second lever member and said secondmember rotate together and being disengaged from said second member whensaid second member is in engagement with said first member, andselectively operable means connected to said second lever member forselectively rotating said second lever member about said rotatablemember.

8. A differential gear assembly comprising a rotatable shaft, a pinioncarrier assembly fixed to said shaft and having first and second pinionsin mutual engagement, said pinion carrier assembly including a housingfixed to said rotatable shaft for rotation therewith and supporting saidfirst and second pinon for rotation about first and second axes,respecively, with said axes located eccentrically relative to the axisof said rotatable shaft, first gear means connected to said first pinionby geared engagement for rotating said first pinion about said firstaxis, second gear means connected to said second pinion by gearedengagement for rotating said second pinion about said second axis, saidhousing comprising a pair of identical housing sections joined togetherat confronting surfaces and having opposite end surfaces, each of saidopposite end surfaces having an axially extending recess concentric withsaid rotatable member and receiving one of said first and second gearmeans, said confronting surfaces having axially extending openingstherein with said openings confronting each other to define a pair ofcavities located side by side and eccentrically relative to saidrotatable shaft, each of said cavities housing one of said pinions andbeing in radial communication with each other whereby said pinion gearsare mutually engaged, said cavities being partially axially ofisetrelative to each other with one of said cavities being in radialcommunication with one of said recesses and with the other of saidcavities being in radial communication with the other of said recesseswhereby said first and second pinions are engaged with said first andsecond gear means, respectively.

9. A differential gear assembly comprising a rotatable shaft, first andsecond worms, a pinion carrier assembly fixed to said shaft and havingfirst and second pinions in mutual engagement, first gear meansconnecting said first Worm and said first pinion by geared engagement,second gear means connecting said second worm and said second pinion bygeared engagement, said pinion carrier assembly including a housingfixed to said rotatable shaft for rotation therewith and supporting saidfirst and second pinions for rotation about axes located eccentricallyrelative to the axis of said rotatable shaft, said first gear meanscomprising a first worm gear and first side gear fixed together andsupported on. said rotatable shaft for rotation relative thereto withsaid first worm gear and first said side gear being in engagement withsaid first worm and said first pinion, respectively, said second gearmeans comprising a second worm gear and second side gear fixed togetherand supported on said rotatable shaft for rotation relative thereto withsaid second wormgear and said second side gear being in engagement withsaid second worm and said second pinion, respectively, said housingcomprising a pair of identical housing sections joined together atconfronting surfaces and having opposite end surfaces, each of saidopposite end surfaces having an axially extending recess concentric withsaid rotatable shaft and receiving one of said first and second sidegears, each of said confronting surfaces having a pair of axiallyextending openings therein With each of said openings of one pair beinglocated coaxially with one of said openings of the other pair to definea pair of cavities eccentrically located relative to said rotatablemember, each of said cavities housing one of said pinions and being inradial communication with each other whereby said pinion gears aremutually engaged and being axially offset relative to each other Withone of said cavities being in radial communication with one of saidrecesses and with the other of said cavities being in radialcommunication with the other of said recesses whereby said first andsecond pinions are engaged with said first and second side gears,respectively.

10. The assembly of claim 9 with said worm gears, said side gears, andsaid pinions all being spur gears.

11. A control assembly for controlling the rotational speed of masterand slave prime movers with each prime mover having a control mechanismoperable for determining its speed, comprising: spring means including aspring member connected directly to the control mechanism of the slaveprime mover 'for biasing that mechanism to a position at which the speedof the slave engine is a selected minimum speed, a rotatable member,differential gear means including said rotatable member and connected tothe master and slave prime movers for sensing their speeds and forproviding a first signal varying in magnitude in accordance withvariations in the magnitude of the rotational speed of the master and asecond signal varying in magnitude in accordance with variations in themagnitude of the rotational speed of the slave and for providingrotation of said rotatable member in one direction responsively to themagnitude of said first signal exceeding that of said second signal andin an opposite direction responsively to the magnitude of said secondsignal exceeding that of said first signal, and means connecting saidrotatable member to the control mechanism of the slave prime mover andfor actuating that mechanism unaifected by the bias of said spring meansfor increasing and decreasing the rotational speed of the slave primemover in accordance with rotation of said rotatable member in said oneand opposite directions, respectively.

References Cited by the Examiner UNITED STATES PATENTS 1,886,975 11/1932Pnofitlich -97 2,100,059 1l/l937 Morehouse 6097 2,105,089 1/1938 Martin6097 2,217,971 10/1940 Smith 6097 2,256,569 9/1941 Kennedy 60-972,262,329 11/1941 McNeil et al 60-97 2,307,334 1/1943 Peek 60-972,339,989 1/1944 Glanville et al. 60-97 2,514,071 7/1950 Jusky 74-7102,666,342 1/1954 Bell 74710 2,782,601 2/1957 Hamilton 60-97 MARTIN P.SCHWADRON, Primary Examiner. ROBERT R. BUNEVICH, Examiner.

1. A CONTROL ASSEMBLY FOR CONTROLLING THE ROTATIONAL SPEED OF MASTER ANDSLAVE PRIME MOVERS HAVING MASTER AND SLAVE CONTROL MECHANISMS,RESPECTIVELY, OPERABLE FOR DETERMINING THEIR SPEEDS, COMPRISING: FIRSTMEANS CONNECTED TO THE MASTER CONTROL MECHANISM AND BEING SELECTIVELYACTUABLE FOR ACTUATING THE MASTER CONTROL MECHANISM, SECOND MEANSCONNECTIBLE TO THE SLAVE CONTROL MECHANISM OF THE SLAVE PRIME MOVER ANDBEING SELECTIVELY ACTUABLE WHEN CONNECTED FOR ACTUATING THE SLAVECONTROL MECHANISM, A ROTATABLE MEMBER, DIFFERENTIAL GEAR MEANS INCLUDINGSAID ROTATABLE MEMBER AND CONNECTED TO THE MASTER AND SLAVE PRIME MOVERSFOR SENSING THEIR SPEEDS AND FOR PROVIDING A FIRST ROTATIONAL SIGNALVARYING IN MAGNITUDE IN ACCORDANCE WITH VARIATIONS IN THE MAGNITUDE OFTHE ROTATIONAL SPEED OF THE MASTER AND A SECOND ROTATIONAL SIGNALVARYING IN MAGNITUDE IN ACCORDANCE WITH VARIATIONS IN THE MAGNITUDE OFTHE ROTATIONAL SPEED OF THE SLAVE AND FOR PROVIDING ROTATION OF SAIDROTATABLE MEMBER IN ONE DIRECTION RESPONSIVELY TO THE MAGNITUDE OF SAIDFIRST SIGNAL EXCEEDING THAT OF SAID SECOND SIGNAL AND IN AN OPPOSITEDIRECTION RESPONSIVELY TO THE MAGNITUDE OF SAID SECOND SIGNAL EXCEEDINGTHAT OF SAID FIRST SIGNAL, CONNECTING MEANS ACTUABLE FOR CONNECTING SAIDROTATABLE MEMBER TO THE SLAVE CONTROL MECHANISM AND FOR ACTUATING THESLAVE CONTROL MECHANISM FOR INCREASING AND DECREASING THE ROTATIONALSPEED OF THE SLAVE PRIME MOVER IN ACCORDANCE WITH ROTATION OF SAIDROTATABLE MEMBER IN SAID ONE AND OPPOSITE DIRECTIONS, RESPECTIVELY, ANDACTUATING MEANS SELECTIVELY ACTUABLE TO ONE CONDITION FOR CONNECTINGSAID SECOND MEANS TO THE SLAVE CONTROL MECHANISM AND FOR DEACTUATINGSAID CONNECTING MEANS AND TO A SECOND CONDITION FOR DISCONNECTING SAIDSECOND MEANS FOR THE SLAVE CONTROL MECHANISM AND FOR ACTUATING SAIDCONNECTING MEANS.